android how to store sensor/accelerometer data into file

public class Main extends Activity implements SensorEventListener {

	private SensorManager mSensorManager;
	private Sensor mAccelerometer;
	private FileWriter writer;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activiy_main);
		mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
		mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
	}

	public void onStartClick(View view) {
		mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
	}

	public void onStopClick(View view) {
		mSensorManager.unregisterListener(this);
	}
	protected void onResume() {
		super.onResume();
		writer = new FileWriter("myfile.txt",true);
	}

	protected void onPause() {
		super.onPause();

		if(writer != null) {
		   writer.close();
		}
	}

	@Override
	public void onAccuracyChanged(Sensor sensor, int accuracy) {

	}

	@Override
	public void onSensorChanged(SensorEvent event) {

		float x = event.values[0];
		float y = event.values[1];
		float z = event.values[2];
		writer.write(x+","+y+","+z+"\n");

	 }
}